Artificial selection was a major model that
Charles Darwin used to explain his theory of
natural selection. It provided a suitable candidate for his study because, due to the long and close interactions that human beings have had with the species that sustain them, there exist relatively extensive intentional or incidental records regarding historical changes in
domestic plant and animal forms. “Believing that it is always best to study some special group,” Darwin himself bred
pigeons.
Artificial selection as it was understood then and today successfully demonstrates two important principles. Firstly, it shows that species
change over time. Animal and plant
breeders had been producing new varieties of existing species for centuries prior to Darwin, and they continue to do so today. Secondly, the change that artificial selection effects is due to differential reproduction within a species in question. While Darwin had no real understanding of the mechanisms of
heredity, he did state that “no breeder doubts how strong is the tendency to inheritance”. In this way, when a
farmer only breeds those of his cows that produce the greatest volume of milk, s/he is bound to end up with progeny that produce a high volume of milk as well.
While its depiction of
differential reproduction accurately reflects that which occurs in nature, artificial selection is different from natural selection in that it selects for an entirely different set of
traits. Domestic plant or animal breeders are invariably most concerned with a plant or animal's financial
profitability, usually aiming to increase its rate of growth or production. And many domesticated species are no longer able to survive without human provision and protection. On the other hand, natural selection selects for individuals that are the best adapted to their
environment.